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G. Szejwach and M. Desbois

Abstract

Cumulative histograms taken from eight consecutive infrared pictures of GOES 1 are used to study the spatio-temporal evolution of mesoscale cloud patterns. A model is proposed to approximate the volume of cloud lying in a particular area. Then, the cloud volume variation between successive pictures in the same area is deduced. This volume variation is used to define a cloud development index. Development or dissipation of cloud formations can be distinguished using this index.

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B. Pinty and G. Szejwach

Abstract

A technique for inferring the spatial and seasonal albodo changes over a whole climatic region from satellite data is developed. This technique uses the diurnal variation of radiances which is measured by geostationary satellites and requires the knowledge of a surface albedo value over at least one reference site. The proposed method is tested over western Africa, using METEOSAT data; and surface albedo maps representative of the wet and dry seasons are derived. With regard to the considered scales and to the achievable accuracies, the technique is shown to be relevant for climatological studies.

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B. Pinty, G. Szejwach, and J. Stum

Abstract

No abstract available.

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D. Ramond, H. Corbin, M. Des̄bois, G. Szejwach, and P. Waldteufel

Abstract

A polar jet stream flowing over northern Europe is investigated using both the radiosounding network and the METEOSAT water vapor (WV) channel imagery. A maximum radiance band associated with the polar jet stream is shown to accurately delineate the tropopause break; a major difference in the subtropical jet stream radiative signature is noted, however. An analytic approximation of the radiative transfer equation is established for the METEOSAT WV channel and leads to the conclusion that the radiance field, away from the polar frontal zones, is representative of the temperature field on a water vapor isosteric surface.

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J. R. Wang, J. L. King, T. T. Wilheit, G. Szejwach, L. H. Gesell, R. A. Nieman, D. S. Niver, B. M. Krupp, and J. A. Gagliano

Abstract

High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended Kaiman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

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